A Lake County judge struck down Indiana's right-to-work ban on certain union fees in a second legal blow to the contentious law passed in 2012.

Lake Circuit Judge George Paras determined the law violates the state constitution by forcing unions to provide services to workers without payment. He wrote in his July 17 ruling that the law was immediately "null and void". Paras determined that the state interjected itself into a federal requirement that unions represent all workers -- whether they pay union fees or not -- when it established criminal penalties for violating the right-to-work law.

The United Steelworkers, which lobbied unsuccessfully against the law in 2011 and 2012, filed the suit against the state.

Indiana became the 23rd state in the nation to ban unions from charging mandatory fees for representation in February 2012; later that year, Michigan Gov. Rick Snyder rushed through legislation making Michigan the 24th state to ban the fees. Indiana's extensive battle on the issue drew thousands of protesters to the Statehouse between 2011 and 2012.

Attorney General Greg Zoeller said Wednesday he would appeal and seek an immediate stay of the ruling.

"Strong opinions exist on both sides about involuntary union dues, but the Attorney General's Office has a duty to defend the laws the Legislature passes," Zoeller said in a statement Wednesday.

Lake Superior Judge John Sedia judge struck down the law last fall in a separate case, but stayed it from taking effect. That case is now being considered by the Indiana Supreme Court.

The International Union of Operating Engineers Local 150, representing northwest Indiana, filed the suit being considered by the state's high court and praised the decision in the sister lawsuit Wednesday.

"We applaud the decision of the Court and congratulate the Steelworkers on successfully dealing another blow to Indiana's ill-conceived 'right to work' law," IUOE Local 150 president-business manager James M. Sweeney said in a statement Wednesday evening.